Drive shaft housing for outboard motors



June 1951 E. c. KIEKHAEFER 2,555,548

DRIVE SHAFT HOUSING FOR OUTBOARD MOTOR Filed April 8, 1949 3 Sheets-Sheet l INVENTOR.

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DRIVE SHAFT HOUSING FOR OUTBOARD MOTOR Filed April 8, 1949 3 Sheets-Sheet 3 f/zbrneys Patented June 5, 1951 OFFICE DRIVE SHAFT HOUSING FOR OUTBOARD MOTORS Elmer C. Kiekhaefer, Cedar-burg, Wis.

Application April 8, 1949, Serial No. 86,143

12 Claims. 1

This invention relates to outboard motors and particularly to the lower structure thereof.

The invention provides a hollow drive shaft housing of improved construction which may be die cast readily and assembled easily while providing the streamlined and functional dimensions required for the efficient operation of the motor.

An object of the invention is to provide a lightweight drive shaft housing and an exhaust chamber of maximum size for receiving the exhaust and discharging the same under water.

Another object is to provide for die casting a drive shaft housing member having an internal exhaust passage extending rearwardly thereof and opening downwardly for discharge into the propeller race.

Another object is to join more securely the drive shaft housing member and the underwater unit carrying the propeller.

Another object is to join the underwater unit directly to the maincasting of the drive shaft housing.

These and other objects and advantages of the invention will be more fully set forth in the following description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevation of an outboard motor with portions thereof broken away and shown in section;

Fig. 2 is a view of the disassembled parts comprising the drive shaft housing;

Fig. 3 is an enlarged view in side elevation of the lower end of the outboard motor shown in Fig. 1 with additional sectioning;

Fig. 4 is an enlarged front elevational View showing the forward recessed tie bolt taken on line 4 l of Fig. 1;

Fig. 5 is an enlarged section taken on line 5"5 of Fig. 1;

Fig. 6 is an enlarged plan of the topof the main casting of the drive shaft housing taken on line 6-6 of Fig. 2;

Fig. '7 is an enlarged transverse section taken on line 1-1 of Fig. 2- and showing the tubular member in section;

Fig. 8-is an enlarged transverse section taken on line ti -8 of Fig. 2;

Fig. 9 is an enlarged transverse section taken on line 9-9 of Fig. 2;

Fig. 10 is an enlarged sectional view taken on line [0-46 of Fig. 2;

Fig. 11 is an enlarged transverse section taken on line II-II of Fig. 2;

Fig. 12 is an enlarged plan view taken on line I2-I2 of Fig. 2; and

Fig. 13 is an enlarged elevation of a part of the lower structure of the motor.

The outboard motor shown in the drawings comprises the engine I, the lower underwater unit 2 including the propeller 3, and the vertical drive shaft 4 extending downwardly from engine lto the lower propeller unit 2 to drive propeller 3. The housing assembly 5 as will be described, encloses shaft 4 and is disposed to receive the exhaust of engine I and discharge the same under water.

The bracket 6 is fitted with the spaced upper and lower resilient rubber bearings 'l and 8, respectively, which rotatably support engine I for turning on a vertical axis to steer the motor. The clamp bracket 9, adapted to be secured to the transom of a boat, not shown, carries bracket 6 for the support of the motor.

Assembly 5 comprises the steel tube or sleeve Ill, the tubular cast housing II, and the upper and lower closure members I2 and I3, respectively, of housing I I.

The upper end of sleeve Ill fits tightly within the cylindrical lower opening I4 of engine I. The lower portion of sleeve I0 is rotatably mounted in bearing 8 and extends downwardly beyond bracket 6. Where dimensional limitations require, the lower portion of sleeve Ill may be of reduced diameter, as shown.

Housing I! comprises a single hollow casting of substantial size and fully open at both the upper end and its base. Housing II is similar to that disclosed and claimed in Patent No.

2,442,728 dated June 1, 1948, for Drive Shaft Housing for Outboard Motors, and includes the annular flange l5 formed integrally with the housing and disposed immediately above the water line of the motor to constitute a splash guard;

The lower streamlined narrow shoe portion I6 of housing I I extending rearwardly forms an inverted channel Il' which opens upwardly at its forward end into the interior or chamber I8 of the housing.

The upper portion of housing I I is of generally increasing, well rounded outer dimensions. The upper end of housing II is flat and preferably substantially larger than sleeve I0 extending and secured therein, as will be described.

The fourribs I9 formed integrally with. housing II extend vertically to the upper end thereof within chamber I8 and are angularly spaced of each other. The machined inwardly facing 3 surfaces 2a of ribs I9 are dimensioned to receive and lit closely the outer diameter of the lower portion of sleeve Ill.

The recess 2| is formed in the forward edge of housing I I immediately beneath flange I5 to receive the forward tie rod 22, as will be described, through the hole 23 in the flat lower wall or step 24.

Member I2 has a central bore 25 to receive sleeve Ill and is seated on the upper end of housing I I. The forward lug 26 of closure member I2 extends downwardly. into the housing between ribs I9 and receives the retaining screw 21 inserted through a hole in the forward edge of the housing. The rear lug 28 of member I2 fits between ribs E9 of housing I! to locate accurately the member. The screw 29 inserted in one side of housing II beneath lug 28 is disposed transversely to tighten housing I on sleeve I and secure the same.

The member I3 closing the base of housing II comprises a single cast plate including a downwardly and rearwardly projecting spout 30 formed integrally therewith at the rear underside thereof. The passage 3| in spout 30 opening through upper side of plate member I3 at the rear end of channel I! in shoe I 8 receives the exhaust gases of engine I discharged downwardly through sleeve Ill into chamber I8 of housing II and the channel.

Plate member I3 is disposed, as shown, above propeller 3 and is of substantial width to serve as an anti-cavitation plate for the propeller. Spout 30 is disposed with respect to propeller 3 so as to discharge the exhaust gases directly into the race of the propeller.

The lower underwater unit 2 includes the cast housing 32 having a fiatupper face fitting the lower machined surface 33 on the underside of plate member I3. The bearing 34 supporting the shaft in housing 32 is secured by the stepped bushing 35 in the upper end of the housing and which fits the undercut opening 86 in member I 3. The seal 3'I'carried within bushing 35 engages shaft 5 extending therethrough to engine I.

- 'The water supply pipe 38 for conducting coolant to the engine is connected at its upper end within openinglt with thecooling system of engine I and extends downwardly through sleeve I0 and housing I I. The lower end of pipe 38 is disposed rearwardly of shaft 4 and extends through the hole 39 in plate I3 into the passage 40 formed within cast housing 32 of lower unit 2. Water circulating means, not shown, within housing 32 provides 'for the supply of water to engine I through pipe 33. Discharge of the water may be variously provided and including discharge with the exhaust of the engine, as described.

The rear tie rod 4| and forward rod 22 secure housings II and 32 together, with anti-cavitation plate I 3 disposed therebetween.

The lower end of tie rod 22 is anchored in the threaded hole at in the upper end of housing 32 near the forward edge thereof. The upper threaded end of rod 22 extends through hole 23 into recess 2! of housing II, as described. The nut 43 securing the upper end of rod 22 is concealed beneath flange I5 in recess 2| in the forward edge of housing I I.

Tie rod ll is anchored at its upper end in the threaded hole M in the top of shoe I6 and extends downwardly within channel Il through plate I3 and the rear lug 55 of housing 32. The nut 46 secures the lower end of rod 4|. Rod 4| is preferably flattened as at 41 between its ends to reduce its frontal area and substantially avoid obstruction of the exhaust gases passing through channel Il for discharge. The lock nut 48 on the upper threaded end of rod 4| serves to secure the rod against turning while the lower unit 2 is being assembled with the drive shaft housing assembly 5.

In the assembly of the outboard motor, engine I and sleeve IE! are first assembled on bracket 6 with pipe 38 extending through sleeve I I] and projecting therefrom. Housing II may be then assembled with member I2 on sleeve It and over pipe 38 and secured to sleeve III by tightening screws 21 and 29. V

The lower unit 2, tie rod 22 and drive shaft 4 are then assembled as a unit with housing I I and rod ii and with plate I3 disposed between housing II and housing 2, as described. The screw 69 passing through plate I3 rearwardly of passage 3| secures the rear end of plate I3 to the underside of shoe I6. I a

The upper end of bushing 35 projecting through plate member I3 fits in the milled circular faces 50 in the lower end of housing II and serves as a guide means for alignment of housing I I, plate I3 and housing 32.

In the operation of the motor, as described, the

exhaust of engine I is discharged into the upper end of sleeve Ill and passes downwardly therethrough into chamber l8. Housing II, being of substantial size and partially submerged in water, effects a cooling and contraction of the exhaust gases which considerably reduces back pressure in the exhaust passage and thereby increases the efficiency of the engine. The exhaust gases pass rearwardly through channel H and are discharged through passage 3| into the race of propeller 3 which effects a further reduction in exhaust pressure.

The holes 5| drilled in the rear of housing II near the upper end thereof provide an exhaust relief when the pressure within the exhaust passage may become excessive as at low speeds of the motor.

The invention provides a light-weight housing construction adapted to be manufactured by low cost die casting. The structural rigidity afforded by the spaced forward and rear tie bolts securing the assembly, as described, makes possible further reductions in weight throughout the mem- .bers.

The upper end of housing I! is preferably as large as practicable. As such, the enlarged upper end will accommodate a single core, not shown, to form the upper interior portion of the housing. The fully open lower end of housing II permits channel I! of shoe I6 and the lower end of housing II also to be formed with a single core, not shown.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim;

1. In an outboard motor including an engine, a sleeve secured to said engine to receive the exhaust thereof, a bracket supporting said sleeve and engine for turning, a lower underwater propeller unit and a drive shaft extending downwardly through said sleeve from said engine'to said propeller unit, a tubular die cast housing member for said drive shaft having upper and lower open enlarged ends and ribs formed therein and engaging the lower end portion of said sleeve to secure the same in place in said cast housing member, the lower end of said. housing extending rearwardly of said propeller unit, plates adapted to close said housing ends, the lower plate having a discharge orifice, and a bolt extending from the intermediate narrower portion of said member securing said propeller unit to the lower end of said cast member with said lower plate disposed therebetween to close the latter and provide for the discharge of exhaust gases rearwardly of said propeller unit.

2. In an outboard motor including an engine, a sleeve secured to said engine to receive the exhaust thereof, a bracket supporting said sleeve and engine for turning, a lower underwater propeller unit and a drive shaft extending downwardly through said sleeve from said engine and connected to said propeller unit, a tubular die cast housing member for said drive shaft having upper and lower open enlarged ends and vertical ribs formed therein extending downwardly from the upper end and engaging the lower end of said sleeve to secure the same and said cast member, the lower end of said cast member extending rearwardly of said propeller unit, plates adapted to close said housing ends, the lower of said plates having a discharge orifice, and means anchored in the narrow intermediate portion of said housing members securing said propeller unit to the lower end of said cast member with said lower plate disposed therebetween to close the latter and provide for the discharge of exhaust gases rearwardly of said propeller unit, said tubular die cast member being of substantial size and having thin walls for substantial cooling of the exhaust gases and elimination of back pressure in the ex- '5 haust passage.

3. In an outboard motor including an engine, a vertical sleeve secured to the lower end of said engine, a bracket rotatably supporting said engine and sleeve, a lower underwater propeller unit, and a drive shaft extending through said sleeve from said engine to the underwater unit; a housing for said drive shaft and from which said lower unit is suspended, comprising a tubular cast member having an open enlarged upper end receiving and enclosing above water the lower end of said sleeve, a closure member disposed at the upper open end of said cast member, and ribs extending vertically within said cast member and formed integrally therewith engaging the circumference of said sleeve to secure the same and support the walls of said member, said mem ber providing an expansion chamber adjacent to the lower end of said sleeve of substantial transverse section and extending upwardly of the lower end of said sleeve between said ribs to said closure member.

luIn an outboard motor including an engine, a vertical sleeve disposed to receive the exhaust of said engine, a bracket rotatably supporting said engine and sleeve, a lower underwater propeller unit, and a drive shaft extending through said sleeve from said engine to said underwater unit; a housing for said drive shaft and from which said lower unit is suspended, comprising a tubular cast member having an open enlarged upper end enclosing the lower end of said sleeve, a closure member disposed immediately beneath said bracket on said sleeve and closing the upper open end of said cast member, and ribs extending vertically within said cast member and formed integrally therewith engaging the circumference of said sleeve to secure the same and support the walls of said member, said cast member being of substantial size extending above and below the 6 lower opening of said sleeve to receive the exhaust therefrom and to constitute an expansion chamber for said exhaust.

5. In an outboard motor including an engine, a vertical sleeve disposed to receive the exhaust of said engine and rotatably support the same, and a drive shaft extending downwardly from said engine through said sleeve; a drive shaft housing including an exhaust passage opening for discharge of the exhaust under water and rearwardly of the motor comprising a hollow cast member secured to the lower length of said sleeve and havin an interior transverse section substantially larger than said sleeve adjacent the latter to provide an exhaust expansion chamber immediate to and extending around and above the lower opening of said sleeve.

6. In an outboard motor including an engine, a lower underwater propeller unit and a drive shaft connecting the engine and propeller unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said propeller unit, said housing comprising a hollow cast upper member having a streamlined open base extending rearwardly of said underwater unit, a plate member disposed between said underwater unit and said upper member generally closing the base of the upper member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, means projecting through an opening in said plate positively securing said underwater unit and upper member in transversely fixed relation and spaced forward and rear tie bolts securing said member and said underwater unit together with said plate member disposed thereoetween.

7. In an outboard motor including anengine, a lower underwater propeller unit and a drive shaft connecting the engine and propeller unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said propeller unit, said housing comprising a hollow cast upper member having a streamlined open base extending rearwardly of said underwater unit, a plate member disposed between said underwater unit and said upper member generally closing the base of said upper member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, a tie rod anchored forwardly in said underwater unit and projecting upwardly into a recess in the forward edge of said cast upper member, and means disposed within said recess securing said rod.

8. In an outboard motor, an engine, a tubular die cast drive shaft housing secured to said engine and adapted to receive exhaust gases there from, an annular flange integrally formed with said cast member immediately above the waterline thereof to constitute a splash guard, an underwater anti-cavitation plate having an opening at the rear thereof for the discharge of exhaust gases of said engine and otherwise closing the base of said cast member, a lower propeller unit including a housing disposed beneath said plate, a tie rod extending from within said member through said plate and secured at the rear of said housing, and a forward tie rod extending from said housing and through said member into a recess in the forward edge thereof and secured therein, said recess being located immediately beneath said splash guard to conceal said recess and the exposed end of said rod.

9. In an outboard motor including an engine, a lower underwater propeller unit and a drive shaft connecting the engine and the underwater unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said underwater unit, said housing comprising a single piece hollow cast member having a streamlined open base in the form of a shoe extending rearwardly of said underwater unit, said underwater unit having an anti-cavitation plate at its upper end disposed to close the open base of said housing member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, and means securing said underwater unit and housing member together including a rear tie bolt extending upwardly and concealed in the mouth of said nozzle and threaded into the rear end of said housing member shoe.

10. In an outboard motor including an engine,

a lower underwater propeller unit and a drive shaft connecting the engine and the underwater unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said underwater unit, said housing comprising a single piece of hollow cast member having a streamlined open base in the form of a shoe extending rearwardly of said underwater unit, said underwater unit having an anti-cavitation plate at its upper end disposed to close the open base of said housing member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, and means securing said underwater unit and housing member together comprising a rear tie bolt extending upwardly and concealed in the mouth of said nozzle and threaded into the rear end of said housing member shoe, a forward tie bolt threaded into said underwater unit and extending upwardly through a ledge of said housing member, and an intermediate tie bolt threaded upwardly from said underwater unit into said housing member at the front of said rearward extension.

11. In an outboard motor including an engine, a lower underwater propeller unit and a drive shaft connecting the engine and the underwater unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said underwater unit, said housing comprising a single piece hollow cast member having a streamlined open base in the form of a shoe extending rearwardly of said underwater unit, said underwater unit having an anti-cavitation plate at its upper end disposed to close the open base of said housing member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, and means securing said underwater unit and housing member together comprising a rear tie bolt extending upwardly and concealed in the mouth of said nozzle and threaded into the rear end of said housing member shoe, a forward tie bolt securing said underwater unit and housing member together forwardly of the drive shaft, and an intermediate tie bolt threaded upwardly from said underwater unit into said housing member at the front of said rearward extension.

12. In an' outboard motor including an engine, a lower underwater propeller unit and a drive shaft connecting the engine and the underwater unit; a drive shaft housing secured at its upper end to said engine and at its lower end to said underwater unit and having a passage receiving the exhaust gases of said engine and discharging the same under water and rearwardly of said underwater unit, said housing comprising a single piece hollow cast member having a streamlined open base in the form of a shoe extending rearwardly of said underwater unit, an anti-cavitation plate at the upper end of said underwater unit disposed to close the open base of said housing member and having an exhaust discharge nozzle projecting downwardly therefrom and rearwardly of said underwater unit, anda drive shaft bearing unit secured in the upper end of said underwater unit by said anti-cavitation plate and projecting upwardly through said plate, said housing member having means at its lower end to laterally engage the projecting portion of said bearing unit and to thereby interlock the underwater unit and housing member against relative lateral movement.

ELMER C. KIEKHAEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'IENTS Number Name Date 1,824,739 Johnson Sept. 22, 1931 1,987,906 Irgens Jan. 15, 1935 2,111,325 Linthwaite Mar. 15, 1938 2,224,900 Conover Dec, 1'7, 1940 FOREIGN PATENTS Number Country Date 332,544 Great Britain July 21, 1930 

